|Publication number||US7862694 B2|
|Application number||US 10/854,238|
|Publication date||Jan 4, 2011|
|Filing date||May 27, 2004|
|Priority date||Jun 24, 2003|
|Also published as||US20040264044|
|Publication number||10854238, 854238, US 7862694 B2, US 7862694B2, US-B2-7862694, US7862694 B2, US7862694B2|
|Inventors||Yoshiyuki Konishi, Masahiro Ueda, Masayasu Suzuki|
|Original Assignee||Shimadzu Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (24), Referenced by (2), Classifications (44), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to a composite coating device for forming a composite coating on a magnetic head and a method of forming a composite coating on a magnetic head.
In a magnetic storage device, a magnetic head is used to record and retrieve data stored in a magnetic storage media. For example, in a hard drive (HD) magnetic storage device in which data is recorded on a magnetic disk, when a magnetic head records and retrieves (access) data, the magnetic head rises from a disk surface only for a predetermined distance. When the magnetic head does not access data, the magnetic head lands on the disk surface in a so-called CSS (contact start and stop) mechanism.
As described above, when the magnetic head does not access data, the magnetic head receives a shock from the disk. The magnetic head also receives a corrosive action through atmospheric moisture and the like, so that wear resistance and corrosion resistance are required for an overcoat of the magnetic head. In addition, as the recording density has been increasing, it is required to reduce a thickness of the overcoat to reduce a distance between an electrode of the magnetic head and a recording layer on the magnetic disk (flight height).
In general, an overcoat of the magnetic head is formed through a manufacturing process comprising (1) a pretreatment process in which a coating surface of a head body is cleaned; (2) a shock absorbing coating formation process in which an amorphous silicon coating is formed; and (3) an overcoat formation process in which a DLC coating is formed. A composite coating device is used to carry out the processes in three independent processing chambers, respectively. The composite coating device performs a sputter etching for the pretreatment process, sputter deposition for the shock absorbing coating formation process, and electron cyclotron resonance plasma chemical vapor epitaxy or cathode arc discharge deposition for the overcoat formation process (refer to Japanese Patent Publication (Kokai) No. 2001-195717).
When the sputter etching is used for the pretreatment process, there is the following problem. An overcoat is formed on a surface of a magnetic head. The surface includes a portion formed of a soft electrode metal, for example, Permalloy, and a portion formed of a hard base metal, for example, AlTic (Al2O3TiC). Accordingly, the portions of the surface are etched at different etch rates, i.e. the portion formed of Permalloy is etched at a higher speed, thereby forming a recessed portion on the surface. As a result, the flight height increases, thereby making it difficult to obtain high recording density.
In view of the problem described above, an object of the present invention is to provide a composite coating device and an overcoat formation method, in which an overcoat is formed on a magnetic head while a flight height in the magnetic recording is reduced.
Further objects and advantages of the invention will be apparent from the following description of the invention.
In order to attain the objects described above, according to a first aspect of the present invention, a composite coating device includes a first processing chamber for performing ion beam etching as a pretreatment process in which an ion beam is irradiated on a surface of a magnetic head at a predetermined angle and the surface is removed for a predetermined depth; a second processing chamber for performing magnetron sputter deposition as a shock absorbing coating formation process in which a shock absorbing coating is formed on the pretreated surface; a third processing chamber for performing electron cyclotron resonance plasma chemical vapor epitaxy as an overcoat formation process in which an overcoat is formed on the surface with the shock absorbing coating formed thereon; and a preparation chamber communicating with the first to third processing chambers through opening and closing means for transferring the magnetic head.
According to a second aspect of the present invention, a composite coating device includes a first processing chamber for performing ion beam etching as a pretreatment process in which an ion beam is irradiated on a surface of a magnetic head at a predetermined angle and the surface is removed for a predetermined depth; a second processing chamber for performing magnetron sputter deposition as a shock absorbing coating formation process in which a shock absorbing coating is formed on the pretreated surface; a third processing chamber for performing cathode arc discharge deposition as an overcoat formation process in which an overcoat is formed on the surface with the shock absorbing coating formed thereon; and a preparation chamber communicating with the first to third processing chambers through opening and closing means for transferring the magnetic head.
According to a third aspect of the present invention, in the composite coating devices in the first and second aspects, an ion beam etching device includes an ion source provided with an electrode for obtaining ions having a first grid with positive potential and a second grid with negative potential; and a communicating portion for eliminating an effect of the potential of the second grid relative to an electron in a plasma production area and for communicating a plasma production area with an outside of the plasma production area. The ion beam etching device may be provided with a dielectric block for adjusting a plasma density distribution at a plasma production portion. The ion beam etching device may also be provided with a high-frequency induction coupled plasma source including an electric insulation dividing wall projecting into the plasma production area and separating the plasma production chamber from outside, and an excitation coil provided in an outer concave portion of the electric insulation dividing wall.
In the composite coating device, the shock absorbing coat is formed of a silicon layer, and the overcoat is formed of a carbon layer. Especially, the silicon layer may be formed of an amorphous silicon, and the carbon layer is formed of one of a diamond-like carbon (DLC) layer or a tetrahedral amorphous carbon (ta-C) layer.
According to the present invention, a method of forming the overcoat on the magnetic head includes steps of the ion beam etching, the magnetron sputter deposition, and the electron cyclotron resonance plasma chemical vapor epitaxy in this order using the composite coating device described above.
According to the present invention, a method of forming the overcoat on the magnetic head may include steps of the ion beam etching, the magnetron sputter deposition, and the cathode arc discharge deposition in this order using the composite coating device described above.
According to the present invention, the magnetic head is formed with one of the overcoat formation methods described above.
Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in
In the embodiment, the composite coating device 1 is used for forming an overcoat on the magnetic head. Before the overcoat formation, an electrode metal, a base metal, and the like are exposed on an overcoat formation surface (protected surface) of the substrate 100. The composite coating device 1 carries out one process in one chamber, so that it is possible to prevent mutual contamination between the processing chambers. Also, the substrate 100 is consecutively processed without being exposed to the atmosphere in the middle of the processing, so that it is possible to prevent oxidation of the substrate 100, sticking of a dust, and the like.
The substrate 100 is transferred to the IBE device 10 from the conveyance chamber 3, and the etching process is carried out on the protected surface in the IBE device 10. In the etching process, the protected surface of the substrate 100 is removed as much as 20 nm in depth as the cleaning process before the amorphous silicon coat is formed. As shown in
The plasma source 13 is a high-frequency induction coupled plasma source for generating plasma through high-frequency induction coupling. A high-frequency introductory window 14 is provided in a plasma chamber 19 of the plasma source 13, and flat-surface excitation coils 15 are provided outside the high-frequency introductory window 14 for generating high frequencies. A RF power source 16 is connected to the excitation coils 15 for supplying a high-frequency electric current of 13.56 MHz. A dielectric material such as quartz, ceramic, and the like is used for the high-frequency introductory window 14. A matching circuit (not shown) is provided between the excitation coil 15 and the RF power source 16 for matching impedance.
In the plasma chamber 19, gas for plasma production is introduced via a gas supply source 17. In the present embodiment, argon gas is used as an example. Grids 18 a, 18 b, and 18 c constituting the electrodes 18 for leading out ions are provided at an opening of the plasma chamber 19. A positive potential V1 is supplied to the grids 18 a via a grid power source 20 a, and a negative potential (−V2) is supplied to the grids 18 b via a grid power source 20 b. The grids 18 c have earth potential Vg, and the plasma chamber 19 has potential (V1) same as that of the grids 18 a.
In the embodiment, an electron port 21 made of a conductive material is provided in the electrodes 18 for leading out ions. The electron port 21 (described below) is attached to the grids 18 a, and has the same potential (V1) as that of the grids 18 a. A substrate holder 23 is provided in the process chamber 12 for holding the substrate 100 as an etching object. The substrate holder 23 is arranged to be tiltable as shown by R1, and rotatable as shown by R2. A vacuum pump (not shown) is connected to an exhaust port 12 a for evacuating the inside of the process chamber 12.
When argon gas is introduced into the plasma chamber 19 and high frequency generated at the excitation coil 15 is introduced into the plasma chamber 19 from the high-frequency introductory window 14, electrons are separated from argon atoms, and plasma including argon ions Ar+ and electrons e are generated. The argon ions Ar+ are accelerated with an electric field between each positive potential grid 18 a and each negative potential grid 18 b and then, decelerated between each grid 18 b and each earth potential grid 18 c. In the end, ion beams IB having energy corresponding to a potential difference between the grids 18 a and the grids 18 c are formed.
The accelerated argon ions Ar+ irradiate on the substrate 100, and etch the surface of the substrate. When the substrate 100 is made of a conducting material, a positive charge of argon ions Ar+ irradiating on the substrate 100 flows to the substrate holder 23 connected to the substrate 100. When the substrate 100 is made of an insulation material such as SiO2, the positive charge is accumulated on the surface of the substrate and the potential of the substrate increases, as shown in
As shown in
When the positive charge is not accumulated on the substrate 100, the electrons e are not led out through the electron port 21. Accordingly, the electrons e corresponding to an amount of the positive charge accumulated on the substrate 100 irradiate on the substrate 100 through the electron port 21 from the plasma chamber 19, so that the positive charge of the substrate 100 is neutralized.
As described above, the electron port 21 is provided in the electrodes 18, and the grids 18 b do not prevent the electrons e from moving toward the process chamber. As a result, the electrons e inside the plasma move toward the electropositive substrate 100 to neutralize the positive charge of the substrate 100, so that the etching effect of the argon ion Ar+ is maintained.
Also, the electrons e irradiate on the substrate 100 for the amount automatically determined by the charged amount of the substrate 100, so that it is not necessary to adjust the amount of the electrons without a problem of too small or too large amount. The electrons e move faster compared to the argon ions Ar+, the electrons e neutralize quickly when the substrate 100 is charged in positive. Specifically, just the electron port 21 is provided in the electrodes 18, thereby reducing cost as compared to a conventional method wherein a heater for thermal emission or another plasma source is provided.
Next, etching characteristics of the substrate 100 with the IBE device will be explained.
As shown in
In addition, when the step d is formed, it is difficult to properly form the amorphous silicon coat 103 and the DLC coat 104. The amorphous silicon coat 103 and the DLC coat 104 have small thicknesses. Accordingly, even though the step d may be small, it is difficult to cover the step, thereby causing a micro-crack or residual stress, and lowering corrosion resistance.
As shown in
After the etching process, the substrate 100 is conveyed to the conveyance chamber 3 and then to the MSD device 30 through the gate 5.
In the coating process, the argon gas is supplied to the sputter chamber 37, and a vacuum device 38 evacuates the inside of the sputter chamber 37, so that the inside of the sputter chamber 37 has a predetermined process pressure and plasma is generated. The Si target 31 is sputtered by the argon ion in the plasma, and sputtered Si particles are accumulated on the coated surface of the substrate 100 and form the amorphous silicon coat.
After the coating process of the amorphous silicon coat, the substrate 100 is conveyed to the conveyance chamber 3 through the gate 6, and then to the ECR-CVD device 40 through the gate 7.
The ECR plasma generation portion 42 is a mechanism for supplying microwave electric power to the magnetic field to generate the electron cyclotron resonance plasma, and for introducing the plasma flow into the reaction chamber 41. A microwave source 46 generates a microwave of 2.45 GHz, and the microwave is introduced into a plasma chamber 47 through a wave guide 46 a to discharge the microwave. In addition, a magnetic flux density 875 G at the ECR condition is formed with the magnetic filed generated by coils 46 b and 46 c to generate electron cyclotron resonance, so that activated ECR plasma is generated. The ECR plasma generated inside the plasma chamber 47 moves toward the substrate 100 inside the reaction chamber 41 along the divergent magnetic field from the plasma window 47 a.
In the bias power source portion 43, a bias power source 43 a is connected to a substrate holding mechanism inside the reaction chamber 41 through a matching unit 43 b, and a negative bias voltage is applied to the substrate 100 disposed inside the reaction chamber 41. A voltage monitor 43 c measures the bias voltage. The reactive gas introduced into the reaction chamber 41 from the reaction gas introductory portion 44 is ionized inside the high density plasma generated by the ECR, and the DLC coat is formed on the substrate 100 with the negative bias voltage. When the DLC coat is formed, ethylene (C2H4), methane (CH4), propane (C3H8), or the like is provided through the reaction gas introductory portion 44 as coating gas. An exhaust pump 44 d exhausts the reaction chamber 20, and a pressure gauge 44 e measures the pressure inside the reaction chamber 20.
Instead of the ECR-CVD device forming the DLC coat, a cathode arc discharge deposition device may form a ta-C (tetrahedral amorphous carbon) coat.
Magnetic coils 55 are provided near an exit of the filter 54 for scanning carbon ion beams, so that the ta-C coat is uniformly formed on the substrate 100. A bias voltage is applied to the substrate 100, and energy of the ions arriving at the substrate 100 depends on the bias voltage, so that the coating characteristics can be adjusted through the bias voltage.
A dielectric window 63 a formed of ceramic and the like is provided at a bottom surface of the plasma chamber 63. The antenna coils 64 are provided at outside the dielectric window 63 a. The antenna coils 64 form a high-frequency magnetic field inside the plasma chamber 63 through the dielectric window 63 a. A cylindrical dielectric block 66 is provided inside the plasma chamber 63 for adjusting a plasma distribution. When plasma production gas (for example, argon gas) is supplied into the plasma chamber 63 through a gas supply device 67 and the antenna coils 64 form the high-frequency magnetic field, plasma P is generated inside the plasma chamber 63. A porous electrode grid G for leading out ions is provided at an opening of the plasma chamber 63. Charged particles such as ions are led out of the plasma chamber 63 via the grid G, and ion-beams IB are accelerated.
In the plasma production portion 61, the cylindrical dielectric block 66 is disposed coaxially with the antenna coils 64. At this moment, the plasma P does not enter an area of the dielectric block including the internal space of the dielectric block 66. As a result, the plasma P is distributed around the dielectric block 66 in a doughnut shape. A density distribution of the plasma P is related to a distribution of an ion current value, i.e. a density distribution of the ion-beams IB. When the density distribution of the plasma has a doughnut shape around the coil shown in
A protrusion 73 a projecting into the plasma production chamber 73 is provided at a midsection of the plasma production chamber 73. An excitation coil 74 is disposed in a concave portion formed outside the protrusion 73 a for forming an alternate current magnetic field M inside the plasma production chamber 73. The protrusion 73 a is formed of an insulator such as glass, ceramic, and the like, and functions as a high-frequency introductory window for introducing the alternate current magnetic field formed by the excitation coil 74 into the plasma production chamber 73. The excitation coil 74 is a solenoid-type coil, and connected to a RF power source 76 through a matching device 75. Incidentally, in the present embodiment, the excitation coil 74 is the solenoid-type coil, and may be a flat-type coil with one tern.
The RF power source 76 uses a frequency from 1 to 100 MHz for an economical reason, and the high-frequency power of 13.56 MHz is used in the present embodiment. A capacitor for matching impedance is provided in the matching device 75. By adjusting a capacitance of the capacitor, a matching condition can be adjusted. When plasma is generated, argon gas or the like is introduced into the plasma production chamber 73 from a gas supply source 77.
Ring-shaped magnets 78 a and 78 b are provided on an outer periphery of the plasma production chamber 73 for forming a static magnetic field in the plasma production chamber 73. The magnets 78 a and 78 b are formed of an electromagnet, and may be formed of a permanent magnet. The magnets 78 a and 78 b form a cusped magnetic field. When the high-frequency voltage is applied to the excitation coil 74, argon gas is excited via inductive coupling, and plasma P1 including the argon ions is generated in a ring-shaped space between the plasma production chamber 73 and the protrusion 73 a. Electrons in the plasma P1 are trapped by the cusped magnetic field, thereby facilitating the plasma production and efficiently forming the plasma P1.
Grids G1, G2, and G3 are provided at an opening of the plasma production chamber 73 for leading out the argon ions from the generated plasma P1. A grid power source 79 applies a grid voltage to the grids G1 to G3. For example, a voltage of 800 V is applied to the grid G1 and a voltage of 400 V is applied to the grid G2, respectively. The grid G3 is grounded and has a potential of 0 V. When the voltages are applied to the grids G1 to G3, the ion beams IB of the argon ions are led out of the plasma source 72 upwardly, and irradiate on the substrate 100.
In the plasma source 72 shown in
Finally, the amorphous silicon coat and the carbon coat formed with the composite coating device 1 of the present embodiment will be explained.
As explained above, according to the present invention, the substrate is tilted by a predetermined angle using the IBE, so that the step between the base metals and the electrode metal can be reduced. Accordingly, it is possible to form the overcoat on the magnetic head with a small flight height.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.
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|U.S. Classification||204/298.34, 204/298.35, 204/298.36, 204/298.01, 204/298.12, 204/298.39, 204/298.41, 118/723.0MA|
|International Classification||C23C14/00, C23C14/32, C23C14/02, G11B5/10, C25B11/00, C23C14/56, G11B5/187, C23C16/54, G11B5/60, C23C16/511, G11B5/127, G11B5/31, G11B5/40, C25B13/00, C25B9/00, G11B5/255, C23C16/00|
|Cooperative Classification||G11B5/3106, G11B5/255, C23C16/54, C23C14/568, G11B5/127, G11B5/40, C23C14/022, G11B5/187, C23C14/325, G11B5/102, C23C16/511|
|European Classification||G11B5/127, G11B5/255, C23C14/56F, C23C14/32A, C23C16/54, G11B5/187, C23C16/511, C23C14/02A2|
|May 27, 2004||AS||Assignment|
Owner name: SHIMADZU CORPORATION, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KONISHI, YOSHIYUKI;UEDA, MASAHIRO;SUZUKI, MASAYASU;REEL/FRAME:015388/0217;SIGNING DATES FROM 20040511 TO 20040512
Owner name: SHIMADZU CORPORATION, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KONISHI, YOSHIYUKI;UEDA, MASAHIRO;SUZUKI, MASAYASU;SIGNING DATES FROM 20040511 TO 20040512;REEL/FRAME:015388/0217
|Jun 4, 2014||FPAY||Fee payment|
Year of fee payment: 4